Patna, June 18: Senior police officials of Patna are passing sleepless nights following the revelation that threat calls to blow up the high security prison at Beur on outskirts of Patna were made from Naxalite-infested Gaya district.

Preliminary police investigation revealed that an anonymous caller made the calls from Chandauti police station area of Gaya, considered to be a Maoist den. The SIM card used for making the calls was purchased only a few days ago.

An investigating officer under the condition of anonymity told The Telegraph that the caller had purchased the SIM card only a week ago and made limited calls. “Limited use of the SIM card has made the task difficult for the police,” the officer said.

What is intriguing is that the circle inspector of Chandauti had been appointed the investigating officer of the case related to arrest of a politburo member of the CPI (Maoist) Jagdish Yadav.

Though Yadav was arrested from an area falling under Guraru police station, the circle inspector of Chandauti, Ram Chandra Yadav, has been assigned to investigate the case. “The involvement of Maoists in making the calls cannot be ruled out,” the police officer said.

The security around the central jail has been tightened after the threat calls. A police team led by superintendent of police (SP) (City) Shivdeep Lande visited the jail on Friday and reviewed the security arrangements. He also visited the cells in which the top Maoists are lodged.

The SP is learnt to have recommended immediate replacement of the home guard jawans from the watchtowers of the jail. The home guard jawans would be replaced by either the Bihar Military Police or the Special Auxiliary Police personnel. Additional security forces have been deployed at the jail to thwart any attempt to blow up the jail. “We know that Maoists don’t carry out such an operation after making it public. But we don’t want to take any chance and hence, security around the jail has been beefed up,” said a senior police officer.

Sources in the jail said that 15-20 Naxalite leaders, including the mastermind of infamous Jehanabad jailbreak, Ajay Kanu, were lodged in the prison. Another central committee member, Pramod Mishra, is also lodged in Beur jail. Mishra was recently taken on remand by an Andhra Pradesh police team.

Around 300 Maoists are presently lodged in the jail. Sources said the closed-circuit camera installed at the jail gate was not functioning when the senior police officers visited the jail on Friday.